Epidemiology of Burkholderia cepacia complex species recovered from cystic fibrosis patients: issues related to patient segregation

Abstract

Studies of the prevalence of Burkholderia cepacia complex species amongst cystic fibrosis (CF) patients in different geographical regions, and the association between cross-infection and putative transmissibility markers, will further our understanding of these organisms and help to address infection-control issues. In this study, B. cepacia complex isolates from CF patients in different regions of Europe were analysed. Isolates were examined for B. cepacia complex species and putative transmissibility markers [cable pilin subunit gene (cblA) and the B. cepacia epidemic strain marker (BCESM)]. Sporadic and cross-infective strains were identified by random amplification of polymorphic DNA (RAPD). In total, 79 % of patients were infected with Burkholderia cenocepacia (genomovar III), 18 % with Burkholderia multivorans (genomovar II) and less than 5 % of patients with B. cepacia (genomovar I), Burkholderia stabilis (genomovar IV) or Burkholderia vietnamiensis (genomovar V). The cblA and BCESM transmissibility markers were only detected in strains of B. cenocepacia. The BCESM was a more sensitive marker for transmissible B. cenocepacia strains than cblA, although sporadic B. cenocepacia strains containing the BCESM, but lacking cblA, were also observed. Furthermore, clusters of cross-infection with transmissibility marker-negative strains of B. multivorans were identified. In conclusion, B. cenocepacia was the greatest cause of crossinfection, and the most widely distributed B. cepacia complex species, within these CF populations. However, cross-infection was not exclusive to B. cenocepacia and cblA and the BCESM were not absolute markers for transmissible B. cenocepacia, or other B. cepacia complex strains. It is therefore suggested that CF centres cohort patients based on the presence or absence of B. cepacia complex infection and not on the basis of transmissibility marker-positive B. cenocepacia as previously suggested. INTRODUCTIONBurkholderia cepacia has emerged as a life-threatening cause of infection in patients with cystic fibrosis (CF). Strains of B. cepacia can be highly transmissible, resulting in patient-topatient spread within and between CF centres (Govan et al., 1993). To date, the most effective strategy to combat B. cepacia infection has been the strict segregation of infected patients. Although successful, the introduction of such a policy has proved controversial and unpopular with many CF patients. Furthermore, segregation will not prevent sporadic acquisition of B. cepacia complex organisms from natural environments .To complicate the clinical problems associated with B. cepacia infection, polyphasic taxonomic studies have now discovered that B. cepacia is a complex of nine genetically distinct species, all capable of causing CF-related infections . Putative transmissibility markers for B. cepacia complex bacteria have now also been identified. These markers include the cable pilin subunit gene (cblA), which encodes a giant cable-like pilus that facilitates adherence to respiratory mucins (Sajj...

Widespread clone of Burkholderia cenocepacia in cystic fibrosis patients in the Czech Republic

“…Hence, understanding the risk posed by the epidemic strains can still be useful for implementing infection control policies in centres that experience such problems. It is worth noting that identification of transmissible strains should be based on genotyping methods and not be confined to markers of transmissibility as they are not absolute markers for epidemic strains (Chen et al, 2001;McDowell et al, 2004). Lack of these markers for definitive identification was also indicated during our study where one sporadic isolate with a unique banding profile (i.e.…”

“…Based on characteristics of the other epidemic strains, we compared the Czech clone CZ1 with Canadian epidemic strains of RAPD 01, 04 and 06 types (Speert et al, 2002) as well as with the ET12 lineage, since the cblA-negative ET12 strain has been recently observed (McDowell et al, 2004). Close similarity between CZ1 and Canadian RAPD 01 was detected by both fingerprinting systems (RAPD and PFGE data are shown in Figs 1 and 2, respectively).…”

Phenotypic diversity and genotypic flexibility of Burkholderia cenocepacia during long-term chronic infection of cystic fibrosis lungs

“…B. cenocepacia is the most prevalent Bcc species colonizing CF patients, with most isolates from the United Kingdom and Canada belonging to a single molecular type (electrophoretic type ET12 or RAPD02) that includes epidemic strain J2315 (Speert et al 2002b;McDowell et al 2004). Along with RAPD02; RAPD01, -04, and -06 comprise a distinct genomic group (previously genomovar IIIA, now called recA subgroup A), whereas other RAPD types belong to a divergent B. cenocepacia genomic group (previously genomovar IIIB, now recA subgroup B) that includes PHDC epidemic lineages HI2424 and AU1054 strains (Johnson 1994;Rozee et al 1994;Mahenthiralingam et al 1996;Speert 2002;Speert et al 2002a;Lipuma 2005;Holden et al 2009;Miller et al 2015).…”

Burkholderia respiratory tract infections in Italian patients with cystic fibrosis: Molecular characterization

“…In recent years, in fact, Bcc has been used in agriculture in biopesticides and bioremedial products, 1 most notably particular strains of B. vietnamiensis and B. ambifaria because of their low incidence of isolation from CF patients. Strategies introduced in different countries have limited the epidemic spread of Bcc 17,34,35 ; so the implementation of stringent infection control measures is important to limit spread both within and outside hospital and epidemiological studies of Burkholderia species are critical to keep pace with the ecological and pathogenic interest in the genus.…”